engleski

Effects of Prestressed Anchors on a High Nailed Wall in Clay

Nailing in clay, in contrast to sand, brings the following disadvantages: shear strength on the surface of contact between the nails and the soil is lower and the critical sliding surface extends deeper in the retained soil. As a result, nails in clay should be longer and more closely spaced than in sand, which makes nailing in clay less economical The nailed wall presented in this paper is located in Dežmanova Street in the very center of the city of Zagreb. Due to its location and a great height, a design of a nailed wall was chosen ; also, in order to prevent movements of the wall and of the retained soil, nailing was combined with prestressed anchors, the lengths of which were adjusted to reach the soil behind the critical shear surface. Three prestressed anchors suitability tests were performed during the construction. The ultimate pull-out resistance was between 400 and 500 kN, i.e. within the expected limits. The movements of the nailed wall along the anchors in the retained soil were measured by using two sliding deformeters to obtain continuous displacement measurements along the axis of the measurement casing. The measurements showed that the displacements were considerably smaller than indicated by the numerical analyses, which was attributed to the lack of a numerical model which would take into consideration the 3D effects. Additionally, the analysis referred to the effect of prestressing that caused a redistribution of the tension forces between the nails and the prestressed anchors. Due to prestressing, the forces in the nails were lessened, which resulted in smaller movements of the wall.

soil nailing; anchors; clay

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